# monit – make broken things work

I set up monit, a utility for monitoring services on a Unix system. My concrete use case is a FreeBSD machine, that runs "N2N Edge", a Peer-to-peer (P2P) virtual private network (VPN) software. monit pretty much automates the "have you tried turning it off and on again?" process. Configurations like the following illustrate this:
check process myproc
matching "myproc"
start program = "/etc/init.d/myprocstart"
stop program = "/usr/bin/killall myproc"
if cpu usage > 95% for 10 cycles then restart

In order to be monitored, every process needes a file containing the process id, when it runs (a so called pidfile). I used the following script to wrap the start_edge script, which in turn holds the actual command to start the VPN software:
#!/usr/local/bin/bash
case $1 in start) echo$\$ > /var/run/edge.pid;
exec 2>&1 /root/start_edge 1>/tmp/edge.out
;;
stop)
killall edge;;
*)
echo "usage: edge {start|stop}" ;;
esac
exit 0

After pkg install monit an example config file can be found at /usr/local/etc/monitrc.sample. I removed the .sample part of the file name and appended the following to the very end:
check process edge
pidfile /var/run/edge.pid
start program = "/usr/bin/edge start"
stop program = "/usr/bin/edge stop"

Make sure to check the config for obvious errors with monit -t, reload the configuration and start the process:
monit reload
monit start all


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